Regulation of enzyme synthesis in aleurone tissue of Avena species

1969 ◽  
Vol 47 (12) ◽  
pp. 2069-2072 ◽  
Author(s):  
J. M. Naylor
Keyword(s):  
Amino Acids ◽  
Hydrolytic Enzymes ◽  
Genetic System ◽  
Enzyme Synthesis ◽  
Hormonal Control ◽  
Physiological System ◽  
Avena Species ◽  
Wild Oats ◽  
Aleurone Tissue ◽  
Regulation Of Enzyme Synthesis

Control of the synthesis of α-amylase in isolated aleurone tissue of an inbred population of wild oats and of the domestic oat variety Torch has been compared. Production of the enzyme in wild oats shows much greater dependence on exogenous gibberellic acid or amino acids than in Torch. It is suggested that this difference reflects variability in a genetic system which determines the degree of hormonal control over the synthesis of hydrolytic enzymes in aleurone of Avena species. Natural selection can be expected to maintain genotypes conferring strong hormonal control of this physiological system in wild oats which depend, for survival, on seed dormancy.

DORMANCY STUDIES IN SEED OF AVENA FATUA: 5. ON THE RESPONSE OF ALEURONE CELLS TO GIBBERELLIC ACID

1966 ◽  
Vol 44 (1) ◽  
pp. 19-32 ◽  
Author(s):  
J. M. Naylor
Keyword(s):  
Amino Acids ◽  
Gibberellic Acid ◽  
Avena Fatua ◽  
Wild Oats ◽  
Aleurone Cells ◽  
Aleurone Tissue ◽  
Primary Action

The synthesis of α-amylase by excised aleurone tissue can be induced by supplying either gibberellic acid (GA) or a mixture of amino acids and sucrose. Aleurone cells form RNA within 4 hours after the imbibition of water or a solution of GA. Synthesis of RNA is essential for the subsequent production of the enzyme. The primary action of GA leading to production of the enzyme begins at about the same time as the first synthesis of RNA. Loss of dormancy during after-ripening involves changes in the response of aleurone cells to gibberellin. Aleurone cells of a non-dormant domestic oat variety Torch exhibit a greater autonomy in the control of α-amylase synthesis than those of wild oats. The current hypothesis that GA acts by genetic derepression is discussed.

Reproduction Versus Somatic Growth: Hormonal Control in Octopus Vulgaris

1978 ◽  
Vol 77 (1) ◽  
pp. 15-31 ◽  
Author(s):  
R. K. O'DOR ◽  
M. J. WELLS
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Muscle Protein ◽  
Somatic Growth ◽  
Hormonal Control ◽  
Gland Secretion ◽  
Total Amino Acid ◽  
Octopus Vulgaris ◽  
Precocious Maturity

Octopus vulgaris can be forced into precocious maturity by removal of the subpedunculate lobe from the brain, an operation that releases the optic glands from inhibition, and allows them to secrete a gonadotropin. 14C-leucine was injected into the bloodstream of immature animals and its subsequent incorporation into muscle protein followed by taking successive samples from the arms. The optic glands were then activated, and a further injection of 3H-leucine given and followed by means of further arm samples. Optic gland secretion suppresses protein synthesis in the muscles. This is associated with an increase in the total amino acid pool in the muscles and with a considerable increase in the concentration of free amino acids circulating in the blood. If an ovary is present these events are associated with a rapid growth of the ovary and its ducts, and a loss of weight elsewhere. In ovariectomized animals the ducts grow, but there is no yolk to absorb the large pool of free amino acids, and the animals gain weight by osmotic uptake of water into the muscles. The developing ovary may produce a hormone that increases the release of amino acids from muscle, since the concentration circulating in the blood of intact animals remains at least as high as in ovariectomized octopuses, despite the demands of the developing ovary. These matters are discussed in relation to other evidence for a gonadial hormone and in relation to the ‘self-destruct’ effect of the optic gland secretion in determining the post-reproductive death of octopuses.

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